Predesigning heterogeneous catalysts on the molecular scale: a unique way to high quality Lidoped MgO and related materials

AKSU Y., Heitz S., Driess M.

IUPAC 44th World Chemistry Congress, İstanbul, Turkey, 11 - 16 August 2013, pp.108, (Full Text)

  • Publication Type: Conference Paper / Full Text
  • City: İstanbul
  • Country: Turkey
  • Page Numbers: pp.108
  • Akdeniz University Affiliated: Yes

Abstract

Due to its low dielectric constant, the low refractive index, high thermal stability and high melting point, magnesium oxide is widely used as inorganic material in many areas, such as fire resistant construction materials, optical materials, protective layers in plasma display panels[1] and buffer layers for different thin films[2] In contrast, lithium-doped magnesium oxide shows high catalytic activity and selectivity in oxidation of methane to the synthetically more useful ethylene[3]. Generally, doped and undoped magnesium oxide can be obtained by thermal decomposition of the corresponding inorganic metal sources, such as carbonates, hydroxides and nitrates[4]. However, this method requires high decomposition temperatures (~750°C) and allows only for a feeble control of material properties, like doping grade, morphology and porosity. The application of single source precursors (SSPs) could be a promising alternative to the classical method. The Li/Mg-ratio can be encoded on the molecular scale and the decomposition of different SSPs delivers materials with different properties.

 

A series of Mg- and Li/Mg-alkoxides was synthesized as SSPs, which were thermally decomposed under different conditions. It was observed, that Li-Mg-alkoxides deliver clean Li-doped magnesium oxides with different Li/Mg-ratios, whereas the decomposition of Mg-alkoxides leads to pure nanocrystalline magnesium oxide. The decomposition pathway of the precursors was investigated via TGA and TG-FTIR and the materials obtained were characterized by PXRD, solid-state-NMR, IR and TEM.

 

 

References

 

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[3] T. Ito, J. H. Lunsford, Nature, 314, 721 (1985).

[4] J. I. Camino, M. J. Holgado, V. Rives, React. Kinet. Catal. Lett., 44(2), 469 (1991).